Search results for "accelerator"
showing 10 items of 1507 documents
Search for the decay Bs0→μ+μ− with the ATLAS detector
2012
A blind analysis searching for the decay B-s(0) -> mu(+)mu(-) has been performed using proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the LHC. W ...
Prospects for probing the gluon density in protons using heavy quarkonium hadroproduction
2001
We examine carefully bottomonia hadroproduction in proton colliders, especially focusing on the LHC, as a way of probing the gluon density in protons. To this end we develop some previous work, getting quantitative predictions and concluding that our proposal can be useful to perform consistency checks of the parameterization sets of different parton distribution functions.
Bosonic quartic couplings at CERN LHC
2004
We analyze the potential of the CERN Large Hadron Collider (LHC) to study anomalous quartic vector-boson interactions Z Z gamma gamma, Z Z Z gamma, W+ W- gamma gamma, and W+ W- Z gamma through the weak boson fusion processes q q -> q q gamma gamma and q q -> q q gamma Z(-> l+ l-) with l = electron or muon. After a careful study of the backgrounds and how to extract them from the data, we show that the process p p -> j j gamma l+ l- is potentially the most sensitive to deviations from the Standard Model, improving the sensitivity to anomalous couplings by up to a factor 10^4 (10^2) with respect to the present direct (indirect) limits.
Beta-decay half-lives of $^{70}$Kr and $^{74}$Rb
2000
Abstract Beta-decay half-lives of two nuclei close to N = Z line, 70 Kr and 74 Rb, have been measured at the ISOLDE mass-separator facility at CERN. Importance of these half-lives on two ingredients explaining existence and development of the Universe, the astrophysical nucleosynthesis and the Standard Model, are discussed.
Measurement of the WW cross section in s=7 TeV pp collisions with the ATLAS detector and limits on anomalous gauge couplings
2012
This Letter reports a measurement of the W W production cross section in root s = 7 TeV pp collisions using data corresponding to an integrated luminosity of 1.02 fb(-1) collected with the ATLAS de ...
Impact of Energy and Luminosity upgrades at LHC on the Physics program of ATLAS
2002
The impact on the physics capabilities of the ATLAS detector of possible LHC upgrades is discussed. As a benchmark, an increase in the luminosity by a factor of ten is considered. For comparison, a doubling of the LHC energy is also explored. Both upgrades significantly enhance the physics capabilities of ATLAS. As measured in terms of the mass reach for new particles, the energy upgrade is more powerful. However, in cases where the effect of an upgrade is to increase the precision of measurements as a result of the larger data samples, the luminosity upgrade can be at least as powerful. The pile-up of minimum bias events at higher luminosity could limit the physics performance of ATLAS in …
Search forB-meson decays tob1ρandb1K*
2009
We present a search for decays of B mesons to final states with a b(1) meson and a rho or K*(d892) meson. The search is based on a data sample consisting of 465 million B (B) over bar pairs collected by the BABAR detector at the SLAC National Accelerator Laboratory. We do not observe any statistically significant signal. The upper limits we set on the branching fractions range from 1.4 to 8.0 x 10(-6) at the 90% confidence level, including systematic uncertainties.
Observation ofBmeson decays toωK*and improved measurements forωρandωf0
2009
We present measurements of B meson decays to the final states {omega}K*, {omega}{rho}, and {omega}f{sub 0}, where K* indicates a spin 0, 1, or 2 strange meson. The data sample corresponds to 465 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. B meson decays involving vector-scalar, vector-vector, and vector-tensor final states are analyzed; the latter two shed new light on the polarization of these final states. We measure the branching fractions for nine of these decays; five are observed for the first time. For most decays we also measure the charge asymmetry and, where relevant, the longitudinal polarization f{sub L}.
Search for decays ofB0mesons intoe+e−,μ+μ−ande±μ∓final states
2008
We present a search for the decays B0→e+e-, B0→μ+μ-, and B0→e±μ using data collected with the BABAR detector at the PEP-II e+e- collider at SLAC. Using a data set corresponding to 384×106 BB pairs, we do not find evidence of any of the three decay modes. We obtain upper limit on the branching fractions, at 90% confidence level, of B(B0→e+e-)<11.3×10-8, B(B0→μ+μ-)<5.2×10-8, and B(B0→e±μ)<9.2×10-8. © 2008 The American Physical Society.
Measurement of the branching fraction, polarization, andCPasymmetries inB0→ρ0ρ0decay, and implications for the CKM angleα
2008
We study B^0→ρ^0ρ^0 decays in a sample of 465×10^6 Υ(4S)→BB events collected with the BABAR detector at the PEP-II asymmetric-energy e^+e^- collider located at the Stanford Linear Accelerator Center (SLAC). We measure the branching fraction B=(0.92±0.32±0.14)×10^(-6) and longitudinal polarization fraction f_L=0.75_(-0.14)^(+0.11)±0.05, where the first uncertainty is statistical and the second is systematic. The evidence for the B^0→ρ^0ρ^0 signal has a significance of 3.1 standard deviations, including systematic uncertainties. We investigate the proper-time dependence of the longitudinal component in the decay and measure the CP-violating coefficients S_L^(00)=(0.3±0.7±0.2) and C_L^(00)=(0.…