Responsible: ElifAsliAlbayrak

Observation of structures in J/psi phi spectrum in exclusive B+ --> J/psi phi K+ decays at 7 TeV: BPH-11-026

Abstract

A peaking structure in the J/psi-phi mass from B+ -> J/psi phi K+ decays has been observed in pp collisions at sqrt(s) = 7 TeV using 5.2 fb-1 of integrated luminosity collected with the CMS detector at the Large Hadron Collider. Fitting the structure to an S-wave relativistic Breit-Wigner lineshapes over a three-body phase-space non-resonant component, gives a signal statistical exceeding 5 standard deviations. The fitted mass and the width values are m = 4148.0 +/- 2.4(stat) +/- 6.3(syst) MeV and Γ = 28 +/- 15 (stat) +/-19 (syst) MeV, respectively. Evidence for an additional peaking structure at higher J/psi phi mass is also reported.

arXiv link: http://arxiv.org/abs/arXiv:1309.6920.

Approved Plots from BPH-11-026 ( click on pdf to get .pdf )

Figure	Abbreviated Caption

Inclusive MuMu Mass. pdf

The J/ψ φ K+ mass distribution with the standard event selection (left) and the tighter requirements (right). The solid curves show the result of fitting these distributions to a Gaussian signal and a second-degree polynomial background while the dashed curves show the background contribution. pdf

The B+ sideband-subtracted K+ K- invariant-mass distribution for J/ψ φ K+ candidates within ± 3 σ of the nominal B+ mass. The solid curve is the result of the fit described in the text. The dashed line shows the zero-candidate baseline. pdf

The number of J/ψ φ K+ candidates as a function of Δ m = m(μ+μ-K+K-)-m(μ+μ-). The solid curve is the global unbinned maximum-likelihood fit of the data, and the dotted curve is the background contribution assuming three-body PS. The band is the ± 1σ uncertainty range for the background obtained from the global fit. The dashed and dash-dotted curves are background curves obtained from two different event-mixing procedures, as described in the text, and normalized to the number of three-body PS background events. The short dashed curve is the 1D fit to the data. pdf

The yield of B+→ J/ψ K+ K- K+ candidates in the data as a function of the K+ K- K+ invariant mass. The error bars represent the statistical uncertainties. The solid curve is the prediction from the PS simulation. pdf

The number of B+ -> J/psi K+ K- K+ candidates as a function of Δm requiring either m(K+K-K+) < 1.68 GeV or m(K+K-K+) > 1.88 GeV (left), or 1.68 < m(K+K-K+) < 1.88 GeV (right). The solid curve is the prediction from the PS simulation. pdf

The sWeighted Δm distribution from the B component pdf

The efficiency corrected Δm spectrum with two signal-hypothesis fit (obtained from the cleaner B sample), B purity is ~60% within 1.5sigma of B mass range. pdf

The Δm spectrums for datasetA (left, dimuon pT>7 GeV), datasetB(right, dimuon pT>7 GeV and each muon pT>4 GeV) with corresponding relative efficiency curves. pdf

The x projection (JpsiPhi space) of dalitz plot for the generated events (shown as red) and for the reconstructed events (shown as black, after all event selections). The dalitz plot is obtained from CMS Phase Space MC. .pdf

The Δm spectrum, including non-B candidates after subtracting the expected PBzs contribution from simulation for candidate events with J/psi phi K+ invariant mass within 1.5 sigma of the B nominal mass. pdf

| | The number of B+ -> J/psi K+ K- K+ candidates as a function of Δm.

The extension of the Δm spectrum, after subtracting non-B background, to the full phase space. The left part, indicated by the red vertical line, is a copy of Fig.3 in the paper. The right part presents the B yields extracted in the seven bins of the previous eliminated region, after subtraction of the B⁰_s background. The blue dashed curve represents the three-body phase-space non-resonant background extrapolated from the left region to the right region. pdf|