147,731 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)
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
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
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
Evidence for the decay B+c→J/ψ3π+2π−
No full textEvidence is presented for the decay B+c → J/ψ 3π+2π− using proton-proton collision data, corresponding to an integrated luminosity of 3 fb−1, collected with the LHCb detector. A signal yield of 32 ± 8 decays is found with a significance of 4.5 standard deviations. The ratio of the branching fraction of the B+c → J/ψ3π+2π− decay to that of the B+c → J/ψ π+ decay is measured to be
B(B+c → J/ψ 3π+2π−)/B(B+c → J/ψ π+� = 1.74 ± 0.44 ± 0.24
where the first uncertainty is statistical and the second is systematic
Measurement of J/Ψ production in pp collisions at √s=7 TeV
No full textThe production of J/psi mesons in proton-proton collisions at root s = 7 TeV is studied with the LHCb detector at the LHC. The differential cross-section for prompt J/psi production is measured as a function of the J/psi transverse momentum p(T) and rapidity y in the fiducial region p(T) is an element of [0; 14] GeV/c and y is an element of [2.0; 4.5]. The differential cross-section and fraction of J/psi from b-hadron decays are also measured in the same p(T) and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2 pb(-1). The measured cross-sections integrated over the fiducial region are 10.52 +/- 0.04 +/- 1.40(-2.20)(+1.64) mu b for prompt J/psi production and 1.14 +/- 0.01 +/- 0.16 mu b for J/psi from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt J/psi production cross-section is obtained assuming no J/psi polarisation and the third error indicates the acceptance uncertainty due to this assumption
57Fe Mössbauer-effect study of preferential site occupancy in quasicrystalline Al86Cr14−xFex alloys
No full textPT: J; CR: BANCEL PA, 1986, PHYS REV B, V33, P7917 BLACK PJ, 1955, ACTA CRYSTALLOGR, V8, P175 CAHN JW, 1986, J PHYS-PARIS, V47, P415 COOPER M, 1966, ACTA CRYSTALLOGR, V20, P614 COOPER M, 1967, ACTA CRYSTALLOGR, V23, P1106 CORBY RN, 1977, ACTA CRYSTALLOGR B, V33, P3468 DUNLAP RA, UNPUB J PHYS F DUNLAP RA, 1986, HYPERFINE INTERACT, V28, P963 DUNLAP RA, 1986, J PHYS F MET PHYS, V16, P1247 DUNLAP RA, 1987, J PHYS F MET PHYS, V17, L39 EIBSCHUTZ M, 1986, PHYS REV LETT, V56, P169 EIBSCHUTZ M, 1987, PHYS REV LETT, V59, P2443 GUYOT P, 1986, J PHYS-PARIS, V47, P389 HAUSER JJ, 1986, PHYS REV B, V33, P3577 HENLEY CL, 1986, PHYS REV B, V34, P797 HENLEY CL, 1987, COMMENTS CONDENSED M, V13, P59 LAWTHER DW, UNPUB MA J, 1986, PHYS REV LETT, V57, P1611 MACKAY AL, 1962, ACTA CRYSTALLOGR, V15, P916 NASU S, 1974, J PHYS F MET PHYS, V4, L24 SCHURER PJ, 1986, SOLID STATE COMMUN, V59, P619 STEPHENS PW, 1986, PHYS REV LETT, V56, P1168 SWARTZENDRUBER LJ, 1985, PHYS REV B, V32, P1383 WARREN WW, 1986, PHYS REV B, V34, P4902; NR: 24; TC: 40; J9: PHYS REV B; PG: 4; GA: P9232Source type: Electronic(1
Precision measurements of B[psi(3686) -> pi(+)pi(-)J/psi] and B[J/psi -> l(+)l(-)]
No full text<p>Based on (106.41 +/- 0.86) x 10(6) psi(3686) events collected with the BESIII detector at the BEPCII collider, the branching fractions of psi(3686) -> pi(+)pi(-)J/psi, J/psi -> e(+)e(-), and J/psi -> mu(+)mu(-) are measured. We obtain B[psi(3686) -> pi(+)pi(-)J/psi] = (34.98 +/- 0.02 +/- 0.45)%, B[J/psi -> e(+)e(-)] = (5.983 +/- 0.007 +/- 0.037)%, and B[J/psi -> mu(+)mu(-)] = (5.973 +/- 0.0007 +/- 0.038)%. The measurement of B[psi(3686) -> pi(+)pi(-)J/psi] confirms the CLEO-c measurement, and is apparently larger than the others. The measured J/psi leptonic decay branching fractions agree with previous experiments within one standard deviation. These results lead to B[J/psi -> l(+)l(-)] = (5.978 +/- 0.005 +/- 0.040)% by averaging over the e(+)e(-) and mu(+)mu(-) channels and a ratio of B[J/psi -> e(+)e(-)]/B[J/psi -> mu(+)mu(-)] = 1.0017 +/- 0.0017 +/- 0.0033, which tests e- mu universality at the four tenths of a percent level. All the measurements presented in this paper are the most precise in the world to date.</p>
A letter from Carl Ma to Charles Smith (August 15, 1997)
No full textThis is a letter from Carl C. H. Ma, son of John Ma (Ma Yuehan; 马约翰) to Charles J. Smith, Director of the International English Language Institute and men's swimming coach at Springfield College, dated August 15, 1997. In the letter Mr. Ma expresses his pleasure at meeting Mr. Smith, and talks about the copied newspaper article on the three-day conference of "Professor John Ma's Scientific Conference on Physical Education of University" and a short Manuscript that he wrote about his father, John Ma, called "My Father and I".To learn more about John Ma, see: https://springfield.as.atlas-sys.com/agents/people/677There were two attached manuscripts to this letter. See items rg105-04-b-03-05-005 and rg105-04-b-03-05-006
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