553 research outputs found
The B_s and D_s decay constants in 3 flavor lattice QCD
Capitalizing on recent advances in lattice QCD, we present a calculation of
the leptonic decay constants f_{B_s} and f_{D_s} that includes effects of one
strange sea quark and two light sea quarks. The discretization errors of
improved staggered fermion actions are small enough to simulate with 3
dynamical flavors on lattices with spacings around 0.1 fm using present
computer resources. By shedding the quenched approximation and the associated
lattice scale ambiguity, lattice QCD greatly increases its predictive power.
NRQCD is used to simulate heavy quarks with masses between 1.5 m_c and m_b. We
arrive at the following results: f_{B_s} = 260 \pm 7 \pm 26 \pm 8 \pm 5 MeV and
f_{D_s} = 290 \pm 20 \pm 29 \pm 29 \pm 6 MeV. The first quoted error is the
statistical uncertainty, and the rest estimate the sizes of higher order terms
neglected in this calculation. All of these uncertainties are systematically
improvable by including another order in the weak coupling expansion, the
nonrelativistic expansion, or the Symanzik improvement program.Comment: 4 page
Land Use Sector Involvement in Mitigation Policies Across Carbon Markets
Different local and international experiences show that the agroforestry sector can be fully included in the global warming mitigation strategies and in the
market mechanisms that may have environmental and socioeconomic benefits. At present, however, the primary sector plays only a minor role in mitigation policies within the UNFCCC and under Kyoto’s Protocol, due to problems and difficulties related to emission/absorption accounting models andmonitoring and standardisation systems. If, on one hand, the progress in science has enabled to overcome accountingrelated problems, on the other, there are no adequate mechanisms to encourage and remunerate the primary sector’s efforts. More specifically, if the primary sector is considered as a source of emissions, it should also be recognised that it has beneficial impacts, notably in economic terms, as carbon sink. Therefore, the definition of clear and internationally shared rules might increase the carbon friendly initiatives and help reduce greenhouse gas emissions. This article is focused on the international experiences that have concerned the primary sector and is intended to supply researchers and policymakers with suggestions and recommendations for implementing local market practices related to carbon credits
Confirmation of the Y(4260) Resonance Production in ISR
Using 13.3 fb^-1 of e+e- collision data taken in the Upsilon(1S-4S) region
with the CLEO III detector at the CESR collider, a search has been made for the
new resonance Y(4260) recently reported by the BaBar Collaboration. The
production of Y(4260) in initial state radiation (ISR), and its decay into
pi+pi-J/psi are confirmed. A good quality fit to our data is obtained with a
single resonance. We determine M(Y(4260))=(4284+17-16(stat)+-4(syst)) MeV/c^2,
Gamma(Y(4260))=(73+39-25(stat)+-5(syst)) MeV/c^2, and
Gamma_ee(Y(4260))xBr(Y(4260)->pi+pi-J/psi)=(8.9+3.9-3.1(stat)+-1.9(syst))
eV/c^2.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006/, Submitted to PRD (Rapid Comm.
Search for Lepton Flavor Violation in Upsilon Decays
In this Letter we describe a search for lepton flavor violation (LFV) in the
bottomonium system. We search for leptonic decays of Upsilon(nS)(n=1,2, and 3)
into muon and tau using the data collected with the CLEO III detector. We
identify the tau lepton using its leptonic decay into electron and utilize
multidimensional likelihood fitting with PDF shapes measured from independent
data samples. We report our estimates of 95% CL upper limits on LFV branching
fractions of Upsilon mesons. We interpret our results in terms of the exclusion
plot for the energy scale of a hypothetical new interaction versus its
effective LFV coupling in the framework of effective field theory.Comment: 10 pages, 3 figures, available through
http://www.lns.cornell.edu/public/CLNS/, submitted to PR
Di-electron Widths of the Upsilon(1S,2S,3S) Resonances
We determine the di-electron widths of the Upsilon(1S), Upsilon(2S), and
Upsilon(3S) resonances with better than 2% precision by integrating the
cross-section of e+e- -> Upsilon over the e+e- center-of-mass energy. Using
e+e- energy scans of the Upsilon resonances at the Cornell Electron Storage
Ring and measuring Upsilon production with the CLEO detector, we find
di-electron widths of 1.354 +- 0.004 (stat) +- 0.020 (syst) keV, 0.619 +- 0.004
+- 0.010 keV, and 0.446 +- 0.004 +- 0.007 keV for the Upsilon(1S), Upsilon(2S),
and Upsilon(3S), respectively.Comment: 9 pages, 4 figures, also available through
http://www.lns.cornell.edu/public/CLNS/2005/, published in PRL; corrected
numerical values in abstrac
Search for Radiative Decays of Upsilon(1S) into eta and eta'
We report on a search for the radiative decay of Upsilon(1S) to the
pseudoscalar mesons eta and etaprime in 21.2 +/- 0.2 times 10^6 Upsilon(1S)
decays collected with the CLEO III detector at the Cornell Electron Storage
Ring (CESR). The eta meson was reconstructed in the three modes eta to
gamma-gamma, eta to pi+pi-pi0 and eta to 3pi0. The etaprime meson was
reconstructed in the mode etaprime to pi+ pi- eta with eta decaying through any
of the above three modes, and also etaprime to gamma rho, where rho decays to
pi^+ pi^-.
Five out of the seven sub-modes are found to be virtually background-free. In
four of them we find no signal candidates and in one Upsilon(1S) to
gamma-etaprime, etaprime to pi+ pi- eta, eta to pi+pi-pi0 there are two good
signal candidates, which is insufficient evidence to claim a signal. The other
two sub-modes eta to gamma-gamma and etaprime to gamma rho are background
limited, and show no excess of events in their signal regions. We combine the
results from different channels and obtain upper limits at the 90% C.L. which
are B(Upsilon(1S) to gamma eta) < 1.0 times 10^-6 and B(Upsilon(1S) to gamma
etaprime) < 1.9 times 10^-6. Our limits are an order of magnitude tighter than
the previous ones and below the predictions made by some theoretical models.Comment: 14 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2007/, Submitted to PR
First Observation of
We report on a study of exclusive radiative decays of the Upsilon(1S)
resonance collected with the CLEO-II detector operating at CESR. We present the
first observation of the radiative decays Upsilon(1S)->gamma pi+pi- and
Upsilon(1S)->gamma pi0pi0. For the dipion mass regime m(pipi)>1.0 GeV, we
obtain Br(Upsilon(1S)->gamma pi+pi-=(6.3+/-1.2+/-1.3) x 10^(-5), and
Br(Upsilon(1S)->gamma pi0pi0=(1.7+/-0.6+/-0.3) x 10^(-5). The observed gamma
pipi events are consistent with the hypothesis Upsilon(1S)->gamma f2(1270).Comment: 9 pages, postscript file also available through
http://w4.lns.cornell.edu/public/CLN
Search for psi(2S)--> eta_c pi^+ pi^- pi^0
Using 5.63 pb^-1 of data accumulated at the psi(2S) resonance with the CLEO
III and CLEO-c detectors corresponding to 3.08 million psi(2S) decays, a search
is performed for the decay psi(2S) -> eta_c pi^+pi^-pi^0 to test a theoretical
prediction based upon the assumption that the c \bar c pair in the psi(2S) does
not annihilate directly into three gluons but rather survives before
annihilating. No signal is observed, and a combined upper limit from six eta_c
decay modes is determined to be B(psi(2S) -> eta_c pi^+pi^-pi^0) < 1.0 x 10^-3
at 90% C.L. This upper limit is about an order of magnitude below the
theoretical expectation.Comment: 8 pages postscript,also available through
http://www.lns.cornell.edu/public/CLNS/2006
Evidence for B^(*)_s bar{B}^(*)_s Production at the Upsilon(5S)
Using data collected by the CLEO III detector at CESR, we started a series of
investigations on the Upsilon(5S) resonance decay properties. The data sample
used for this analysis consists of 0.42 fb-1 of data taken on the Upsilon(5S)
resonance, 6.34 fb-1 of data collected on the Upsilon(4S) and 2.32 fb-1 of data
taken in the continuum below the Upsilon(4S). B_s mesons are expected to decay
predominantly into D_s meson, while the lighter B mesons decay into D_s only
about 10% of the time. We exploit this difference to make a preliminary model
dependent estimate of the ratio of B_s(*) anti-B_s(*) to the total b anti-b
quark pair production at the Upsilon(5S) energy to be (21 +- 3 +- 9)%.Comment: 17 pages postscript,also available through
http://www.lns.cornell.edu/public/CONF/2004/, Presented at ICHEP Aug
16-22,2004, Beijing, Chin
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