129 research outputs found
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Quarkonium Spectroscopy and New States from BaBar
We review results on charmonium and bottomonium spectroscopy by the BaBar experiment at the PEP-II e{sup +}e{sup -} collider at SLAC. More space is reserved to the new results like the observation of hadronic non-B{bar B} {Upsilon}(4S) decays and the investigation on the production and decay properties of the recently discovered charmonium-like states X(3872) and Y (4260). These results are preliminary, unless otherwise specified
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Recent heavy flavor results from the Tevatron
The CDF and D0 experiments at the Tevatron p{bar p} collider have pioneered and established the role of flavor physics in hadron collisions. A broad program is now at its full maturity. We report on three new results sensitive to physics beyond the standard model, obtained using the whole CDF dataset: a measurement of the difference of CP asymmetries in K{sup +}K{sup -} and {pi}{sup +}{pi}{sup -} decays of D{sup 0} mesons, new bounds on the B{sub s}{sup 0} mixing phase and on the decay width difference of B{sub s}{sup 0} mass-eigenstates, and an update of the summer 2011 search for B{sub (s)}{sup 0} mesons decaying into pairs of muons. Finally, the D0 confirmation of the observation of a new hadron, the {chi}{sub b}(3P) state, is briefly mentioned
Mass Corrections to Flavor-Changing Fermion-Graviton Vertices in the Standard Model
In a previous study, the flavor-changing fermion-graviton interactions have
been analyzed in the framework of the standard model, where analytical results
for the relevant form factors were obtained at the leading order in the
external fermion masses. These interactions arise at one-loop level by the
charged electroweak corrections to the fermion-graviton vertex, when the
off-diagonal flavor transitions in the corresponding charged weak currents are
taken into account. Due to the conservation of the energy-momentum tensor, the
corresponding form factors turn out to be finite and gauge invariant when
external fermions are on-shell. Here we extend this previous analysis by
including the exact dependence on the external fermion masses. Complete
analytical results are provided for all the relevant form factors to the
flavor-changing fermion-graviton transitions.Comment: 19 pages, 9 figure
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Simulation of Prompt Emission from GRBs with a Photospheric Component and its Detectability By GLAST
The prompt emission from gamma-ray bursts (GRBs) still requires a physical explanation. Studies of time-resolved GRB spectra, observed in the keV-MeV range, show that a hybrid model consisting of two components, a photospheric and a non-thermal component, in many cases fits bright, single-pulsed bursts as well as, and in some instances even better than, the Band function. With an energy coverage from 8 keV up to 300 GeV, GLAST will give us an unprecedented opportunity to further investigate the nature of the prompt emission. In particular, it will give us the possibility to determine whether a photospheric component is the determining feature of the spectrum or not. Here we present a short study of the ability of GLAST to detect such a photospheric component in the sub-MeV range for typical bursts, using simulation tools developed within the GLAST science collaboration
Measurement of the Charge Collection Efficiency after Heavy Non-Uniform Irradiation in BaBar Silicon Detectors
We have investigated the depletion voltage changes, the leakage current
increase and the charge collection efficiency of a silicon microstrip detector
identical to those used in the inner layers of the BaBar Silicon Vertex Tracker
(SVT) after heavy non-uniform irradiation. A full SVT module with the front-end
electronics connected has been irradiated with a 0.9 GeV electron beam up to a
peak fluence of 3.5 x 10^14 e^-/cm^2, well beyond the level causing substrate
type inversion. We irradiated one of the two sensors composing the module with
a non-uniform profile with sigma=1.4 mm that simulates the conditions
encountered in the BaBar experiment by the modules intersecting the horizontal
machine plane. The position dependence of the charge collection properties and
the depletion voltage have been investigated in detail using a 1060 nm LED and
an innovative measuring technique based only on the digital output of the chip.Comment: 7 pages, 13 figures. Presented at the 2004 IEEE Nuclear Science
Symposium, October 18-21, Rome, Italy. Accepted for publication by IEEE
Transactions on Nuclear Scienc
Lenses in the forest: cross-correlation of the Lyman-alpha flux with CMB lensing
We present a theoretical estimate for a new observable: the cross-correlation
between the Lyman-alpha flux fluctuations in quasar (QSO) spectra and the
convergence of the cosmic microwave background (CMB) as measured along the same
line-of-sight. As a first step toward the assessment of its detectability, we
estimate the signal-to-noise ratio using linear theory. Although the
signal-to-noise is small for a single line-of-sight and peaks at somewhat
smaller redshifts than those probed by the Lyman-alpha forest, we estimate a
total signal-to-noise of 9 for cross-correlating QSO spectra of SDSS-III with
Planck and of 20 for cross-correlating with a future polarization based CMB
experiment. The detection of this effect would be a direct measure of the
neutral hydrogen-matter cross-correlation and could provide important
information on the growth of structures at large scales in a redshift range
which is still poorly probed by observations.Comment: 5 pages, 4 figures, matches published versio
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