70,717 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 J/ψ production in pp collisions at s√=2.76TeV
No full textThe production of J/ψ mesons is studied with the LHCb detector using data from pp collisions at s√=2.76 TeV corresponding to an integrated luminosity of 71 nb−1. The differential cross-section for inclusive J/ψ production is measured as a function of its transverse momentum p T. The cross-section in the fiducial region 0 < p T < 12 GeV/c and rapidity 2.0 < y <4.5 is measured to be 5.6 ± 0.1 (stat) ± 0.4 (syst) μb, with the assumption of unpolarised J/ψ production. The fraction of J/ψ production from b-hadron decays is measured to be (7.1 ± 0.6 (stat) ± 0.7 (syst))%
Production of J/ψ and Υ mesons in pp collisions at s√=8 TeV
No full textThe production of J/ψ and Υ mesons in pp collisions at s√=8 TeV is studied with the LHCb detector. The J/ψ and Υ mesons are reconstructed in the μ + μ − decay mode and the signal yields are determined with a fit to the μ + μ − invariant mass distributions. The analysis is performed in the rapidity range 2. 0 < y < 4. 5 and transverse momentum range 0 < p T < 14 (15) GeV/c of the J/ψ (Υ) mesons. The J/ψ and Υ production cross-sections and the fraction of J/ψ mesons from b-hadron decays are measured as a function of the meson p T and y
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
Searches for B0(s)→J/ψppˉ and B+→J/ψppˉπ+ decays
No full textThe results of searches for B0(s)→J/ψ pp¯ and B + → J/ψ p p¯ π+ decays are reported. The analysis is based on a data sample, corresponding to an integrated luminosity of 1.0 fb−1 of pp collisions, collected with the LHCb detector. An excess with 2.8 σ significance is seen for the decay B0s→J/ψ pp¯ and an upper limit on the branching fraction is set at the 90 % confidence level: B(B0s→J/ψ pp¯) < 4.8 × 10−6, which is the first such limit. No significant signals are seen for B0 → J/ψ pp¯ and B+ → J/ψ pp¯ π + decays, for which the corresponding limits are set: B(B0→J/ψ pp¯) < 5.2 × 10−7, which significantly improves the existing limit; and B(B+→J/ψ pp¯π+) < 5.0 × 10−7, which is the first limit on this branching fraction
Correction to: NG2 antigen is involved in leukemia invasiveness and central nervous system infiltration in MLL-rearranged infant B-ALL (Leukemia, (2018), 32, 3, (633-644), 10.1038/leu.2017.294)
No full textThe original version of this Article contained an error in the spelling of the author Juan Carlos Rodriguez-Manzaneque, which was incorrectly given as J Carlos Rodríguez-Manzaneque. This has now been corrected in both the PDF and HTML versions of the Article
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy 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
NN from Colombia collected by L. Ramos, E. Álvarez, J. Cabezas, J. Rodriguez & C. Ibañez #14
No full textFile Name: TOLI-25068-RAN-01-12-F-14.jpg
CÓDIGO FOTO: TOLI-25068-RAN-01-12-F-14-
Fotografía: SI
Nº TOLI: TOLI-25068
PARCELA: RAN-01
CÓDIGO: 12-F-14
Nº COLECTA: 14
NUEVOS COLECTORES: Laura Isabel Ramos
COLECTORES: L. Ramos, E. Álvarez, J. Cabezas, J. Rodriguez & C. Ibañez
Nº MUESTRAS MONTADAS: 1
Homologación: No homologado
Nueva fecha del evento : 20/12/2018.
Fecha del evento: 27/11/2018.
Proyecto : Recursos Botánicos Disponibles en Línea (BRAVO) para la flora Colombiana
Hábitat: Bosque húmedo tropical (bh-T)
Continente: SA
Pais: Colombia
Estado/Provincia: Meta
Municipio: Puerto López
Centro poblado / Cabecera municipal: La Serranía
Localidad: Reserva Natural El Amparo
Elevación minima en metros: 200
Elevación maxima en metros: 250
Latitud: 4.020
Longitud original: -72.600
datum geodésico: WGS 84
Latitud decimal: 4.020
Longitud decimal: -72.600
Nombre cientifico: NN
Reino: Plantae
Filo: Magnoliophyta
Clase: Equisetopsida
Orden: Malpighiales
Familia nueva: Clusiaceae
Género nuevo: NN
: Clusiaceae
genero herbario: NN
Especie de herbario para TNRS: NN
Especie corregida herbario y desde TNRS: Indet indet
Familia corregida desde TNRS: Clusiaceae
: 4084</p
NN from Colombia collected by L. Ramos, E. Álvarez, J. Cabezas, J. Rodriguez & C. Ibañez #13
No full textFile Name: TOLI-24032-RAN-01-14-F-13.jpg
CÓDIGO FOTO: TOLI-24032-RAN-01-14-F-13-
Fotografía: SI
Nº TOLI: TOLI-24032
PARCELA: RAN-01
CÓDIGO: 14-F-13
Nº COLECTA: 13
NUEVOS COLECTORES: Laura Isabel Ramos
COLECTORES: L. Ramos, E. Álvarez, J. Cabezas, J. Rodriguez & C. Ibañez
Nº MUESTRAS MONTADAS: 1
Homologación: No homologado
Nueva fecha del evento : 20/12/2018.
Fecha del evento: 27/11/2018.
Proyecto : Recursos Botánicos Disponibles en Línea (BRAVO) para la flora Colombiana
Hábitat: Bosque húmedo tropical (bh-T)
Continente: SA
Pais: Colombia
Estado/Provincia: Meta
Municipio: Puerto López
Centro poblado / Cabecera municipal: La Serranía
Localidad: Reserva Natural El Amparo
Elevación minima en metros: 200
Elevación maxima en metros: 250
Latitud: 4.020
Longitud original: -72.600
datum geodésico: WGS 84
Latitud decimal: 4.020
Longitud decimal: -72.600
Nombre cientifico: NN
Reino: Plantae
Filo: Magnoliophyta
Clase: Equisetopsida
Orden: Magnoliales
Familia nueva: Annonaceae
Género nuevo: NN
: Annonaceae
genero herbario: NN
Especie de herbario para TNRS: NN
Especie corregida herbario y desde TNRS: Indet indet
Familia corregida desde TNRS: Annonaceae
: 3116</p
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