19,911 research outputs found
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
No full textFirst evidence of the B 0 → J / ψ ω decay is found and the B s 0 → J / ψ η and B s 0 → J / ψ η ′ decays are studied using a dataset corresponding to an integrated luminosity of 1.0 fb -1 collected by the LHCb experiment in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV. The branching fractions of these decays are measured relative to that of the B 0 → J / ψ ρ 0 decay:frac(B (B 0 → J / ψ ω), B (B 0 → J / ψ ρ 0)) = 0.89 ± 0.19 (stat) - 0.13 + 0.07 (syst),frac(B (B s 0 → J / ψ η), B (B 0 → J / ψ ρ 0)) = 14.0 ± 1.2 (stat) - 1.5 + 1.1 (syst) - 1.0 + 1.1 (frac(f d, f s)),frac(B (B s 0 → J / ψ η ′), B (B 0 → J / ψ ρ 0)) = 12.7 ± 1.1 (stat) - 1.3 + 0.5 (syst) - 0.9 + 1.0 (frac(f d, f s)), where the last uncertainty is due to the knowledge of f d / f s, the ratio of b-quark hadronization factors that accounts for the different production rate of B 0 and B s 0 mesons. The ratio of the branching fractions of B s 0 → J / ψ η ′ and B s 0 → J / ψ η decays is measured to befrac(B (B s 0 → J / ψ η ′), B (B s 0 → J / ψ η)) = 0.90 ± 0.09 (stat) - 0.02 + 0.06 (syst)
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Measurement of the branching fraction
No full textThe B
0
s
→ J/ψK
0
S
branching fraction is measured in a data sample corresponding to 0.41 fb−1
of integrated luminosity collected with the LHCb detector at the LHC. This channel is sensitive to
the penguin contributions affecting the sin 2β measurement from B
0
→ J/ψK
0
S
. The time-integrated
branching fraction is measured to be B(B
0
s
→ J/ψK
0
S
) = (1.83±0.28)×10−5
. This is the most precise
measurement to date
Measurement of the time-dependent CP asymmetry in B0 -> J/ψ KS0 decays
No full textThis Letter reports a measurement of the CP violation observables SJ/ψK0S and CJ/ψK0S in the decay channel B0→J/ψK0S performed with 1.0 fb−1 of pp collisions at s√=7 TeV collected by the LHCb experiment. The fit to the data yields SJ/ψK0S=0.73±0.07(stat)±0.04(syst) and CJ/ψK0S=0.03±0.09(stat)±0.01(syst). Both values are consistent with the current world averages and within
expectations from the Standard Model
Measurement of the B0–B0 oscillation frequency Δmd with the decays B0→D−π+ and B0→ J/ψK∗0
No full textThe B
0
–B
0
oscillation frequency Δmd is measured by the LHCb experiment using a dataset corresponding
to an integrated luminosity of 1.0 fb−1
of proton–proton collisions at √
s = 7 TeV, and is found to be
Δmd
=0.5156±0.0051 (stat.)±0.0033 (syst.) ps−1
. The measurement is based on results from analyses
of the decays B
0
→ D
−π
+ (D
−
→ K
+π
−π
−) and B
0
→ J/ψK
∗0
(J/ψ →μ
+μ
−,K
∗0
→ K
+π
−) and
their charge conjugated modes
SIMPLIFIED MODELING OF HIGH-J FAR-INFRARED AND MICROWAVE SPECTRA OF TETRAHEDRAL MOLECULES
No full text W. G. Harter and C. W. Patterson, J. Chem. Phys. 66, 4872-4885 (1977); C. W. Patterson and W. G. Harter, J. Chem. Phys. 66, 4886-4892 (1977). H. W. Galbraith, C. W. Patterson, B. J. Krohn, and W. G. Harter, J. Mol. Spectrosc. 73, 475-493 (1978).Author Institution:We use the and symmetric-top representations for rapidly rotating spherical-top molecules to approximate the clustered values of and diagonal coefficients with 3-J symbols. These coefficients then specify the intensities and wavenumbers, respectively, of absorption lines for the ``forbidden’’ pure rotational transitions in the vibrational ground state of tetrahedral molecules. We predict the absorption to be strongest for those states which correspond to rotation about the axes, and which satisfy the selection rule , Model spectra for (far-infrared) and (microwave) transitions will be shown
Observation of the Lambda(0)(b) -> J/psi p pi(-) decay
No full textThe first observation of the Cabibbo-suppressed decay Λ b → J/ψpπ is reported using a data sample of proton-proton collisions at 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb-1. A prominent signal is observed and the branching fraction relative to the decay mode Λ b → J/ψpK is determined to be B (Λb → J / ψp π-/ B Λ b → J / ψp K- = 0.0824 ± 0.0025 stat ± 0.0042 syst. A search for direct CP violation is performed. The difference in the CP asymmetries between these two decays is found to be A CP (Λb → J / ψp π-) - A CP (Λb → J / ψp K-) = + 5.7 ± 2.4 stat ± 1.2 syst %, which is compatible with CP symmetry at the 2.2σ level. [Figure not available: see fulltext.] © 2014 The Author(s)
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
No full textFirst observations of the B0s
→ψ(2S)η, B0 →ψ(2S)π
+
π
− and B0s
→ψ(2S)π
+
π
− decays are made
using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in
proton–proton collisions at a centre-of-mass energy of
√
s = 7 TeV. The ratios of the branching fractions
of each of the ψ(2S) modes with respect to the corresponding J/ψ decays are
B(B0s
→ψ(2S)η)
÷
B(B0s
→J/ψη)
= 0.83± 0.14 (stat)±0.12 (syst) ±0.02 (B),
;
B(B0→ψ(2S)π
+
π
−
)
÷
B(B0→J/ψπ
+
π
−
)
= 0.56± 0.07 (stat)±0.05 (syst)± 0.01 (B),
;
B(B0s
→ψ(2S)π
+
π
−
)
÷
B(B0s
→J/ψπ
+
π
−
)
= 0.34± 0.04 (stat)±0.03 (syst)± 0.01 (B),
where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψ
and ψ(2S) meson decays
Control and Filtering for Discrete Linear Repetitive Processes with H infty and ell 2--ell infty Performance
No full textRepetitive processes are characterized by a series of sweeps, termed passes, through a set of dynamics defined over a finite duration known as the pass length. On each pass an output, termed the pass profile, is produced which acts as a forcing function on, and hence contributes to, the dynamics of the next pass profile. This can lead to oscillations which increase in amplitude in the pass to pass direction and cannot be controlled by standard control laws. Here we give new results on the design of physically based control laws for the sub-class of so-called discrete linear repetitive processes which arise in applications areas such as iterative learning control. The main contribution is to show how control law design can be undertaken within the framework of a general robust filtering problem with guaranteed levels of performance. In particular, we develop algorithms for the design of an H? and dynamic output feedback controller and filter which guarantees that the resulting controlled (filtering error) process, respectively, is stable along the pass and has prescribed disturbance attenuation performance as measured by and – norms
Methodology for ion neutralization at solid/electrolyte interfaces
No full textPT: J; CR: ADELMAN SA, 1974, J CHEM PHYS, V61, P4242 ADELMAN SA, 1975, J CHEM PHYS, V62, P4908 ADELMAN SA, 1976, J CHEM PHYS, V64, P2375 ANDERSON PW, 1961, PHYS REV, V124, P41 BLANDIN A, 1976, J PHYSIQUE, V37, P369 BLOSS W, 1978, SURF SCI, V72, P277 BOCKRIS JOM, 1963, P ROY SOC LOND A MAT, V274, P55 BRAKO R, 1981, SURF SCI, V108, P253 BRAKO R, 1984, PHYS REV B, V30, P5629 BRAKO R, 1985, PHYS SCR, V32, P451 BRAKO R, 1985, SOLID STATE COMMUN, V55, P633 CHAMBERS LG, 1976, INTEGRAL EQUATIONS S, P114 CIZEK J, 1969, ADV CHEM PHYS, V14, P35 EASA SI, 1985, SURF SCI, V161, P129 GRIMLEY TB, 1983, SURF SCI, V124, P305 MAKOSHI K, 1984, J PHYS SOC JPN, V53, P2441 MCDOWELL HK, 1982, CHEM PHYS, V72, P451 MCDOWELL HK, 1982, J CHEM PHYS, V77, P3263 MCDOWELL HK, 1985, J CHEM PHYS, V83, P772 MORRISON SR, 1980, ELECTROCHEMISTRY SEM, P31 NEWNS DM, 1969, PHYS REV, V178, P1123 NEWNS DM, 1983, PHYS SCRIPTA, V6, P5 PARENT LG, 1984, J ELECTROANAL CH INF, V163, P23 SCHMICKLER W, 1979, J ELECTROANAL CHEM, V100, P533 SCHMICKLER W, 1980, J ELECTROANAL CH INF, V113, P159 SCHUGARD M, 1977, J CHEM PHYS, V66, P2534 SEBASTIAN KL, 1981, SURF SCI, V110, L571 SEBASTIAN KL, 1983, PHYS LETT A, V98, P39 SEBASTIAN KL, 1985, PHYS REV B, V31, P6976 SHANKAR R, 1982, PRINCIPLES QUANTUM M, P482 SROUBEK Z, 1981, SPRINGER SERIES CHEM, V17, P277 TULLY JC, 1980, ANNU REV PHYS CHEM, V31, P319 WATSON GN, 1966, TREATISE THEORY BESS YEAGER E, 1982, SURF SCI, V101, P1; NR: 34; TC: 18; J9: J ELECTROANAL CHEM; PG: 12; GA: C8849Source type: Electronic(1
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