3,355 research outputs found
Observation of the Λb0→J/ψΞ-K+ decay
No full textUsing proton–proton collision data corresponding to an integrated luminosity of 140fb-1 collected by the CMS experiment at s=13TeV, the Λb0→J/ψΞ-K+ decay is observed for the first time, with a statistical significance exceeding 5 standard deviations. The relative branching fraction, with respect to the Λb0→ψ(2S)Λ decay, is measured to be B(Λb0→J/ψΞ-K+)/B(Λb0→ψ(2S)Λ)=[3.38±1.02±0.61±0.03]%, where the first uncertainty is statistical, the second is systematic, and the third is related to the uncertainties in B(ψ(2S)→J/ψπ+π-) and B(Ξ-→Λπ-)
Observation of Bs0→J/ψK*(892)0 [B subscript s superscript 0 → J / psi K* (892) superscript 0] and Bs0→J/ψKS0 [B subscript s superscript 0 → J / psi K subscript s superscript 0 ] decays
No full textWe report the first observation of two Cabibbo-suppressed decay modes of the Bs0 [B subscript s superscript 0] meson. Using a sample of pp̅ collisions at √s=1.96 [square root of 1.96] TeV corresponding to 5.9 fb-1 [fb superscript -1] of integrated luminosity collected with the CDF II, the collider detector at the Fermilab Tevatron, we search for new Bs0 [B subscript s superscript 0] decay modes in a sample of events containing J/ψ→μ+μ- [J / psi→mu superscript + mu superscript -] decays. We reconstruct a Bs0→J/ψK*(892)0 [B subscript s superscript 0→J / psi K subscript s superscript 0] signal with K*(892)0→K+π- [K* (892) superscript 0 →K superscript + pi superscript -], observing a yield of 151±25 events with a statistical significance of 8.0σ [8.0 delta]. We also reconstruct a Bs0→J/ψKS0 [B subscript s superscript 0→J / psi K subscript s superscript 0] signal with KS0→π+π- [K subscript s superscript 0→ pi superscript + pi superscript -], observing a yield of 64±14 events with a statistical significance of 7.2σ [7.2 delta]. From these yields, we extract the branching ratios B(Bs0→J/ψK*(892)0)=(8.3±3.8)×10-5 [B (B subscript s superscript 0→J / psi K* (892) superscript 0) = (8.3±3.8) × 10 superscript -5] and B(Bs0→J/ψK0)=(3.5±0.8)×10-5 [B (B subscript s superscript 0→J / psi K superscript 0) = (3.5 ± 0.8) × 10 superscript -5], where statistical, systematic, and fragmentation-fraction uncertainties are included in the combined uncertainty.United States. Dept. of EnergyNational Science foundation (U.S.)Alfred P. Sloan Foundatio
QCD Highlights from CMS
No full textWe present recent and legacy Quantum Chromodynamics (QCD) physics results based on jet final states from the CMS experiment at the LHC. The accumulated data were acquired from proton+proton collisions at center-of-mass energies of 8 and 13 TeV and integrated luminosity up to 19 fb and 35.8 fb respectively. Proton+lead collision results are also presented at 5.02 TeV
Observation of diffractive J/psi production at the Fermilab Tevatron
No full textWe report the first observation of diffractive J/psi(--> mu (+)mu (-)) production in collisions at roots = 1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum p(T)(mu) > 2 GeV/c within the pseudorapidity region \ eta \ production rates is found to be R-J/psi = [1.45 +/- 0.25]%. ne ratio R-J/psi(X) is presented as a function of x-Bjorken. By combining it with our previously measured corresponding ratio R-jj(x) for diffractive dijet production, we extract a value of 0.59 +/- 0.15 for the gluon fraction of the diffractive structure function of the proton
Measurement of J/ψ and ψ(2S) prompt double-differential cross sections in pp collisions at √s =7 TeV.
No full textPublished by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.The double-differential cross sections of promptly produced J/ψ and ψ(2S) mesons are measured in pp collisions at √s =7 TeV, as a function of transverse momentum p_{T} and absolute rapidity |y|. The analysis uses J/ψ and ψ(2S) dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and 4.90 fb^{-1}, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to p_{T}=120 and 100 GeV for the J/ψ and ψ(2S), respectively, when integrated over the interval |y|<1.2. The ratio of the ψ(2S) to J/ψ cross sections is also reported for |y|<1.2, over the range 10<p_{T}<100 GeV. These are the highest p_{T} values for which the cross sections and ratio have been measured
Observation of the Y (4140) structure in the J/psi phi mass spectrum in B-+/- -> J/psi phi K-+/- decays
No full textThe observation of the Y ( 4140) structure in B-+/- -> J/psi phi K-+/-
decays produced in (p) over barp collisions at root s = 1.96 TeV is
reported with a statistical significance greater than 5 standard
deviations. A fit to the J/psi phi mass spectrum is performed assuming
the presence of a Breit-Wigner resonance. The fit yields a signal of 19
+/- 6 (stat) +/- 3 (syst) resonance events,, resonance mass, width
of 4143.4(-3.0)(+2.9) ( stat) +/- 0.6 (syst) MeV/c(2),
15.3(-6.1)(+10.4) (stat) +/- 2.5 (syst) MeV/c(2), respectively. The
parameters of this resonance-like structure are consistent with values
reported from an earlier CDF analysis
Measurement of the decay amplitudes of B-0 -> J/psi K*(0) and B-S(0) -> J/psi phi decays
No full textAn angular analysis of B-0 --> J/psi K*(0) and B-s(0) --> J/psi phi has been used to determine the decay amplitudes with parity-even longitudinal (A(0)) and transverse (A(\ \)) polarization and parity-odd transverse (A1(-)) polarization. The measurements are based on 190 B-0 and 40 B-s(0) candidates obtained from 89 pb(-1) of (p) over barp collisions at the Fermilab Tevatron. The longitudinal decay amplitude dominates with \A(0)\(2) = 0.59 +/- 0.06 +/- 0.01 for B-0 and \A(0)\ (2) = 0.61 +/- 0.14 +/- 0.02 for B-s(0) decays. The parity-odd amplitude is found to be small with \A1(-)\(2) = 0.13(-0.09)(+0.12) +/- 0.06 for B-0 and \A1(-)\ = 0.23 +/- 0.19 +/- 0.04 for B-s(0) decays
Analysis of the quantum numbers J(PC) of the x(3872) particle
No full textWe present an analysis of angular distributions and correlations of the X(3872) particle in the exclusive decay mode X(3872)-> J/psi pi(+)pi(-) with J/psi ->mu(+)mu(-). We use 780 pb(-1) of data from p (p) over bar collisions at root s=1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We derive constraints on spin, parity, and charge conjugation parity of the X(3872) particle by comparing measured angular distributions of the decay products with predictions for different J(PC) hypotheses. The assignments J(PC)=1(++) and 2(-+) are the only ones consistent with the data
Measurement of branching ratio and Bs0 lifetime in the decay Bs0→J/ψf0(980) at CDF
No full textWe present a study of B[subscript s][superscript 0] decays to the CP-odd final state J/ψf[subscript 0](980) with J/ψ→μ+μ- and f0(980)→π[superscript +]π[superscript -]. Using pp̅ collision data with an integrated luminosity of 3.8 fb[superscript -1] collected by the CDF II detector at the Tevatron we measure a B[subscript s][superscript 0] lifetime of τ(B[subscript s][superscript 0]→J/ψf[subscript 0](980))=1.70[subscript -0.11][superscript +0.12](stat)±0.03(syst)ps. This is the first measurement of the B[subscript s][superscript 0] lifetime in a decay to a CP eigenstate and corresponds in the standard model to the lifetime of the heavy B[subscript s][superscript 0] eigenstate. We also measure the product of branching fractions of B[subscript s][superscript 0]→J/ψf[subscript 0](980) and f0(980)→π[superscript +]π[superscript -] relative to the product of branching fractions of B[subscript s][superscript 0]→J/ψϕ and ϕ→K[superscript +]K[superscript -] to be R[subscript f0/ϕ]=0.257±0.020(stat)±0.014(syst), which is the most precise determination of this quantity to date.National Science Foundation (U.S.)United States. Dept. of EnergyAlfred P. Sloan Foundatio
Erratum to: Search for new physics in dijet angular distributions using proton-proton collisions at
No full textErratum to: Eur. Phys. J. C (2018) 78:789 https://doi.org/10.1140/epjc/s10052-018-6242-x
In this article the author name Luigi Calligaris was incorrectly written as A. Calligaris. The original article has been
corrected
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