118146740
The intrinsic and oscillated astrophysical neutrino flavor ratios
The pp interactions taking place in the cosmos around us are a source of the astrophysical neutrinos of all the three flavors. In these interactions, the electron and the muon neutrinos mainly come from the production and the decay of the \pi^{\pm} mesons, whereas the tau neutrinos mainly come from the production and the decay of the D^{\pm}_{S} mesons. We estimate the three intrinsic neutrino flavor ratios for 1 GeV 10^{-10} in the presence of neutrino oscillations, where L is the distance to the astrophysical neutrino source in units of parsecs.
3069819
Test of factorization hypothesis from exclusive nonleptonic B decays
We investigate the possibility of testing the factorization hypothesis in nonleptonic exclusive decays of the B meson. In particular, we consider the nonfactorizable ${B}^{0}\ensuremath{\rightarrow}{D}^{(*)+}{D}_{s}^{(*)\ensuremath{-}}$ modes and ${B}^{0}\ensuremath{\rightarrow}{D}^{(*)+}({\ensuremath{\pi}}^{\ensuremath{-}},{\ensuremath{\rho}}^{\ensuremath{-}})$ known as well-factorizable modes. By taking the ratios $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}^{(*)+}{D}_{s}^{(*)\ensuremath{-}})/\mathcal{B}[{B}^{0}\ensuremath{\rightarrow}{D}^{(*)+}({\ensuremath{\pi}}^{\ensuremath{-}},{\ensuremath{\rho}}^{\ensuremath{-}})],$ we find that under the present theoretical and experimental uncertainties there is no evidence for the breakdown of the factorization description for heavy-heavy decays of the B meson.
118999114
CP violation in the semileptonic B(lepton 4) (B ---> D pi lepton neutrino) decays: multi - Higgs doublet model and scalar leptoquark models
$\mathrm{CP}$ violation from physics beyond the standard model is investigated in ${B}_{l4}$ decays: $\stackrel{\ensuremath{\rightarrow}}{B}D\ensuremath{\pi}l{\overline{\ensuremath{\nu}}}_{l}.$ In the decay process, we include various excited states as intermediate states decaying to the final hadrons, $D+\ensuremath{\pi}$. We consider the semileptonic decay to a tau lepton family as well. $\mathrm{CP}$ violation is implemented through complex scalar-fermion couplings in the multi-Higgs-doublet model and scalar-leptoquark models beyond the standard model. With these complex couplings, we calculate the $\mathrm{CP}$-odd rate asymmetry and the optimal asymmetry. We find that for ${B}_{\ensuremath{\tau}4}$ decays the optimal asymmetry is sizable and can be detected at $1\ensuremath{\sigma}$ level with about ${10}^{6}\char21{}{10}^{7}B$-meson pairs, for maximally allowed values of $\mathrm{CP}$-odd parameters in those extended models.
126179603
Measurement of |V(ub) / V(cb)| (and |V(ub)|) in exclusive nonleptonic decays within the generalized factorization scheme
Within the generalized factorization scheme, we study extracting $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ by calculating the ratios $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}({\ensuremath{\pi}}^{+},{\ensuremath{\rho}}^{+}))/\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{D}_{s}^{(*)\ensuremath{-}}{D}^{(*)+})$ including penguin effects. The ratios involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode have considerable penguin corrections $(\ensuremath{\sim}15%$ at the amplitude level), but those involving the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{*+}$ mode have relatively small penguin corrections. On the other hand, the ${B}^{0}\ensuremath{\rightarrow}{D}_{s}^{\ensuremath{-}}{D}^{+}$ mode has a smaller form-factor dependence. Therefore, these ratios complement each other in measuring ${V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}.$ The theoretical uncertainty from the hadronic form factors in our method is at the level of 20%, which is comparable to the model dependence uncertainty of about 20% in the measurement of $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|$ from the exclusive semileptonic B decays. Using the newest upper limit on $\stackrel{\ensuremath{\rightarrow}}{B}{D}_{s}\ensuremath{\pi}$ decay from CLEO, our method sets an upper limit $|{V}_{\mathrm{ub}}{/V}_{\mathrm{cb}}|l0.13$ which is very close to the measured values from the semileptonic B decays.
120805024
Search for First Generation Scalar Leptoquarks in pp Collisions at $\sqrt{s}=7$ TeV with the ATLAS Detector
We report a search for first generation scalar leptoquarks using 1.03 fb−1 of proton–proton collisions data produced by the Large Hadron Collider at and recorded by the ATLAS experiment. Leptoquarks are sought via their decay into an electron or neutrino and a quark, producing events with two oppositely charged electrons and at least two jets, or events with an electron, missing transverse momentum and at least two jets. Control data samples are used to validate background predictions from Monte Carlo simulation. In the signal region, the observed event yields are consistent with the background expectations. We exclude at 95% confidence level the production of first generation scalar leptoquark with masses when assuming the branching fraction of a leptoquark to a charged lepton is equal to 1.0 (0.5).
118704582
Dark energy from forgetting
We suggest that dark energy has a quantum informational origin. Landauer's principle associated with the erasure of quantum information at a cosmic horizon implies the non-zero vacuum energy having effective negative pressure. Assuming the holographic principle, the minimum free energy condition, and the Gibbons-Hawking temperature for the cosmic event horizon we obtain the holographic dark energy with the parameter $d\simeq 1$, which is consistent with the current observational data. It is also shown that both the entanglement energy and the horizon energy can be related to Landauer's principle.
96502755
Charged-particle multiplicities inppinteractions measured with the ATLAS detector at the LHC
New Journal of Physics The open–access journal for physics Charged-particle multiplicities in pp interactions measured with the ATLAS detector at the LHC The ATLAS Collaboration New Journal of Physics 13 (2011) 053033 (68pp) Received 22 December 2010 Published 19 May 2011 Online at http://www.njp.org/ doi:10.1088/1367-2630/13/5/053033 Measurements √ are presented from proton–proton collisions at centre-of-mass energies of s = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum- bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks √ with p T > 100 MeV, is measured to be 3.483 ± 0.009 (stat) (syst) at s = 0.9 TeV and 5.630 ± 0.003 (stat) ± 0.169 (syst) at s = 7 TeV. Abstract. New Journal of Physics 13 (2011) 053033 © 2011 CERN for the benefit of the ATLAS Collaboration, published under licence by IOP Publishing Ltd for the Institute of Physics and Deutsche Physikalische Gesellschaft. Content may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation and DOI.
126168504
Neutrino Masses, Lepton Flavor Violations, and Flavor Changing Neutral Currents in the Composite Little Higgs Model
28653980
The expected performance of the ATLAS inner detector
The ATLAS experiment [1] is a general purpose detector designed to exploit the discovery potential of the Large Hadron Collider (LHC) at CERN, which will provide protonproton collisions at a center of mass energy of 14 TeV. The Inner Detector will see of the order of 1000 charged particle tracks for every bunch crossing at the design luminosity of the LHC. A summary of the expected performance for reconstructing single particles is presented, along with some measures of the vertex resolution of the vertexing capabilities. The studies focus on the performance expected for the initial running at the start-up of the LHC.