3,792,113 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′
Get PDFFirst 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 CP-violating phase \phi s in Bs->J/\psi\pi+\pi- decays
Get PDFMeasurement of the mixing-induced CP-violating phase phi_s in Bs decays is of prime importance in probing new physics. Here 7421 +/- 105 signal events from the dominantly CP-odd final state J/\psi pi+ pi- are selected in 1/fb of pp collision data collected at sqrt{s} = 7 TeV with the LHCb detector. A time-dependent fit to the data yields a value of phi_s=-0.019^{+0.173+0.004}_{-0.174-0.003} rad, consistent with the Standard Model expectation. No evidence of direct CP violation is found
Observations of Bºs→ψ(2S)η and Bº(s)→ψ(2S)π+π- decays
Get PDFFirst 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
Study of B c + → J / ψ D s + and B c + → J / ψ D s ∗ + decays in pp collisions at s = 13 TeV with the ATLAS detector
No full textAbstract
A study of
B
c
+
→
J
/
ψ
D
s
+
and
B
c
+
→
J
/
ψ
D
s
∗
+
decays using 139 fb−1 of integrated luminosity collected with the ATLAS detector from
s
= 13 TeV pp collisions at the LHC is presented. The ratios of the branching fractions of the two decays to the branching fraction of the
B
c
+
→ J/ψπ+ decay are measured:
B
B
c
+
→
J
/
ψ
D
s
+
/
B
B
c
+
→
J
/
ψπ
+
= 2.76 ± 0.47 and
B
B
c
+
→
J
/
ψ
D
s
∗
+
/
B
B
c
+
→
J
/
ψπ
+
= 5.33 ± 0.96. The ratio of the branching fractions of the two decays is found to be
B
B
c
+
→
J
/
ψ
D
s
∗
+
/
B
B
c
+
→
J
/
ψ
D
s
∗
+
= 1.93 ± 0.26. For the
B
c
+
→
J
/
ψ
D
s
∗
+
decay, the transverse polarization fraction, Γ±±/Γ, is measured to be 0.70 ± 0.11. The reported uncertainties include both the statistical and systematic components added in quadrature. The precision of the measurements exceeds that in all previous studies of these decays. These results supersede those obtained in the earlier ATLAS study of the same decays with
s
= 7 and 8 TeV pp collision data. A comparison with available theoretical predictions for the measured quantities is presented
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
Get PDFThe 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 J/ψ production in pp collisions at s√=2.76TeV
Get PDFThe 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
Get PDFThe 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
Marriner S. Eccles, correspondence with Congressman Laurence J. Burton
No full textCorrespondence of Marriner S. Eccles with Laurence J. Burton, U.S. Representative from Utah. Topics discussed included overpopulation and U.S. involvement in the Vietnam War. Includes a reprint of two articles about the war by Eric Norden and Dave Dellinger, originally published in the February 1966 issue of Liberation magazine
Measurement of J/ψ polarization in pp collisions at √s=7 TeV
Get PDFAn angular analysis of the decay J/ψ→μ+μ− is performed to measure the polarization of prompt J/ψ mesons produced in pp collisions at √s=7TeV. The dataset corresponds to an integrated luminosity of 0.37 fb−1 collected with the LHCb detector. The measurement is presented as a function of transverse momentum, pT, and rapidity, y, of the J/ψ meson, in the kinematic region 2<pT<15GeV/c and 2.0<y<4.5
Measurement of the branching fraction
Get PDFThe 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
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