63 research outputs found
Hadronic Mass Moments in Inclusive Semileptonic B Meson Decays
We have measured the first and second moments of the hadronic mass-squared
distribution in B -> X_c l nu, for P(lepton) > 1.5 GeV/c. We find <M_X^2 -
M_D[Bar]^2> = 0.251 +- 0.066 GeV^2, )^2 > = 0.576 +- 0.170
GeV^4, where M_D[Bar] is the spin-averaged D meson mass.
From that first moment and the first moment of the photon energy spectrum in
b -> s gamma, we find the HQET parameter lambda_1 (MS[Bar], to order 1/M^3 and
beta_0 alpha_s^2) to be -0.24 +- 0.11 GeV^2. Using these first moments and the
B semileptonic width, and assuming parton-hadron duality, we obtain |V_cb| =
0.0404 +- 0.0013.Comment: 11 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Observation of the Charmed Baryon at CLEO
The CLEO experiment at the CESR collider has used 13.7 fb of data to
search for the production of the (css-ground state) in
collisions at {\rm GeV}. The modes used to
study the are ,
, , , and
. We observe a signal of 40.49.0(stat) events
at a mass of 2694.62.6(stat)1.9(syst) {\rm MeV/}, for all modes
combined.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
Evidence of New States Decaying into
Using 13.7 of data recorded by the CLEO detector at CESR, we report
evidence for two new charmed baryons: one decaying into
with the subsequent decay , and its
isospin partner decaying into followed by
. We measure the following mass differences
for the two states: =318.2+-1.3+-2.9 MeV,
and =324.0+-1.3+-3.0 MeV. We interpret
these new states as the particles, the charmed-strange
analogs of the .Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
Measurement of the Relative Branching Fraction of to Charged and Neutral B-Meson Pairs
We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to
determine the production ratio of charged to neutral B-meson pairs produced at
the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ ->
J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to
extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+B-)/Gamma(Y(4S) ->
B0\bar{B0}) = = 1.04 +/- 0.07(stat) +/- 0.04(syst). With the assumption that
f+- + f00 = 1, we obtain f00 = 0.49 +/- 0.02(stat) +/- 0.01(syst) and f+- =
0.51 +/- 0.02(stat) +/- 0.01(syst). This production ratio and its uncertainty
apply to all exclusive B-meson branching fractions measured at the Y(4S)
resonance.Comment: 11 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
First Observation of the Decays and B^{0}\to D^{*-}p\bar{n}$
We report the first observation of exclusive decays of the type B to D^* N
anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs
collected with the CLEO detector operating at the Cornell Electron Storage
Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton
\pi^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-}
proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons
are identified by their annihilation in the CsI electromagnetic calorimeter.Comment: 9 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
A Search for
We report results of a search for in a sample of 9.7 million
charged meson decays. The search uses both and
decay modes of the , and demands exclusive reconstruction of the
companion decay to suppress background. We set an upper limit on the
branching fraction at 90%
confidence level. With slight modification to the analysis we also establish
at 90% confidence
level.Comment: 10 ages postscript, also available through
http://w4.lns.cornell.edu/public/CLN
Two-body B Meson Decays to eta and eta': Observation of B->eta K*
In a sample of 19 million produced B mesons, we have observed the decays B ->
eta K* and improved our previous measurements of B -> eta'K. The branching
fractions we measure for these decay modes are BR(B+ -> eta K*+) = (26.4
+9.6-8.2 +- 3.3) x , BR(B0 -> eta K*0) = (13.8 +5.5-4.6 +- 1.6) x
, BR(B+ -> eta' K+) = (80 +10-9 +- 7) x and BR(B0 -> eta'
K0) = (89 +18-16 +- 9) x . We have searched with comparable
sensitivity for related decays and report upper limits for these branching
fractions.Comment: 12 page postscript file, 2 figure
Determination of the Strong Phase in D0 -> K+pi- Using Quantum-Correlated Measurements
We exploit the quantum coherence between pair-produced D0 and D0bar in
psi(3770) decays to study charm mixing, which is characterized by the
parameters x and y, and to make a first determination of the relative strong
phase \delta between D0 -> K+pi- and D0bar -> K+pi-. Using 281 pb^-1 of e^+e^-
collision data collected with the CLEO-c detector at E_cm = 3.77 GeV, as well
as branching fraction input and time-integrated measurements of R_M =
(x^2+y^2)/2 and R_{WS} = Gamma(D0 -> K+pi-)/Gamma(D0bar -> K+pi-) from other
experiments, we find \cos\delta = 1.03 +0.31-0.17 +- 0.06, where the
uncertainties are statistical and systematic, respectively. By further
including other mixing parameter measurements, we obtain an alternate
measurement of \cos\delta = 1.10 +- 0.35 +- 0.07, as well as x\sin\delta = (4.4
+2.7-1.8 +- 2.9) x 10^-3 and \delta = 22 +11-12 +9-11 degrees.Comment: 5 pages, also available through
http://www.lns.cornell.edu/public/CLNS/2007/. Incorporated referees' comment
First Measurement of
We present the first measurement of the D*+ width using 9/fb of e+e- data
collected near the Upsilon(4S) resonance by the CLEO II.V detector. Our method
uses advanced tracking techniques and a reconstruction method that takes
advantage of the small vertical size of the CESR beam spot to measure the
energy release distribution from the D*+ -> D0 pi+ decay. We find the D*+ width
equals 96+/-4(Statistical)+/-22(Systematic) keV. We also measure the energy
release in the decay and compute m(D*+)-m(D0) =
145.412+/-0.002(Statistical)+/-0.012(Systematic) MeV/c**2.Comment: 10 pages postscript, also available through
http://w4.lns.cornell.edu/public/CLNS, submitted to PR
Search for W W/W Z resonance production in âÎœqq final states in pp collisions at âs=13 TeV with the ATLAS detector
A search is conducted for new resonances decaying into a W W or W Z boson pair, where one W boson decays leptonically and the other W or Z boson decays hadronically. It is based on proton-proton collision data with an integrated luminosity of 36.1 fb â1 collected with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of s=13 TeV in 2015 and 2016. The search is sensitive to diboson resonance production via vector-boson fusion as well as quark-antiquark annihilation and gluon-gluon fusion mechanisms. No significant excess of events is observed with respect to the Standard Model backgrounds. Several benchmark models are used to interpret the results. Limits on the production cross section are set for a new narrow scalar resonance, a new heavy vector-boson and a spin-2 Kaluza-Klein graviton.[Figure not available: see fulltext.]
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