56,171 research outputs found
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
The 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
Letter from Carl Hayden to P. J Moran
Letter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
Letter from P. J. Moran to Carl Hayden
Letter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trail
Letter from P. J. Moran to Carl Hayden
Letter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trai
Telegrams Between Carl Hayden to P. J. Moran, Democratic County Central Committee
Telegram from Carl Hayden to P. J. Moran regarding the resignation of W. W. Crosby and his replacement J. R. Eakin
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
Spectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Evidence for the decay B0→J/ψω and measurement of the relative branching fractions of meson decays to J/ψη and J/ψη′
First 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)
Promotion of cardiovascular health in preschool children: 36-month cohort follow-up
Background Educational interventions in preschool children could improve dietary behavior and physical activity, and prevent unhealthy body weights in low- and middle-income countries. Previously, we have reported the beneficial impact of an educational intervention in preschoolers in a 6-month trial. We now report extended results after 36 months. Methods Evaluating the cohort of previously intervened children, baseline measurements were made in May 2009 in 14 preschool facilities in Usaquén (Bogotá, Colombia). Follow-up measurements were performed at 18 and 36 months. The primary outcome was the mean change in children's knowledge and attitudes scores regarding healthy eating and living an active lifestyle, including habits scores related to physical activity. Secondary outcomes were the change over time of children's nutritional status and the mean change in parent's knowledge, attitudes, and habits. Results We included 1216 children, 3-5 years of age, and 928 parents. After adjusting by sex and age of children, socioeconomic status, age of parents, and age and education level of teachers, we found a significant increase in mean knowledge, attitudes, and habits scores at 36 months, compared with baseline: 87.94 vs 76.15 (P <.001); 86.39 vs 57.03 (P <.001); and 66.29 vs 48.72 (P <.001), respectively. We observed a similar increase in knowledge and attitude scores in parents: 73.45 vs 70.01 (P <.001); and 78.08 vs 74.65 (P <.001). The proportion of eutrophic children increased from 62.1% at baseline to 75.0% at 36 months (P <.0001). Conclusions After 36 months, the educational intervention maintained a beneficial trend toward a healthy lifestyle in children and their parents. © 2013 Elsevier Inc. All rights reserved
Portrait of Amy Mack (Mrs Lancelot Harrison) [picture] /
Title from inscription on reverse.; Condition: Fair, glued to card.; Inscriptions: "Amy Mack (Mrs. Lancelot Harrison) author of 'A bush calendar', 'Bush days', etc. photo. J. S. P. Ramsay" --In ink on reverse
Measurement of the branching fraction
The 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
- …
